Thread cutting die



`Aug. `21, 1934. l., NlKoLoFF THREAD CUTTING DIEk '2 sheets-sheet 1 Filed oct. 15. 195o 'llllllIrlllllll/llllllllly Inman/iai".- L M5677/ MZ:

Patented And. 21, 1934 Lil-,23%

.ea-rear l THREAD CUTTING DIE `Luben Nikoloff, Boston, Mass.

Application Getober 15, 1930, Serial No. 488,833

` v19 claims. (o1. 1x1-.120)

This invention relates to a thread-cutting die having certain novel and improved features, namely, rirst, thread-cutting Chasers which` may be removed when worn or broken and replaced by'new ones; and second, hard inserts set into the body of the die stock to receive the wear of the chasers. There are disclosed in this application several novel features. which are not claimed herein, namely, iirst, means for adjusting the body and consequently the chasers to Vary the diameter of the screw to be cut; second', a blank guide which is axially adjustable with relation to the body, and in the Case of an adjustable body is self-adjusting to compensate for adjustment of the body; third, improved handles by which the die stock is manipulated; and` fou-1th, a bevel at the nrst end of thev Chaser to bevel off the end of the blank or stock, in Case the latterv issornewhat over-size. These features are the'subject matter of a divisional application. Y

The invention will best be'understood by reference to the following description, when taken in connection with the accompanying drawings of three illustrative embodiments thereof, while its scope will be pointed out more particularly in the appended claims.

In the drawings:

Fig. 1 is an elevation, partly inY vertical section, of one form or embodiment of theA invention;

Fig. 2 is an elevation at an enlarged scale of a portion or" Fig. l; v

Fig. 3 is a sectional View on line 3-3 of Fig. 2;

Fig. 4 is a sectional View on line {lf-4 of Fig. 2;

Fig. 5 is a sectional View on line 5-'5 of Fig. 2;

Fig. o is a perspective View of one of the thread-V cutting chasers shown in Figs. l'to 5, inclusive;

Fig. 7 is an elevation, partly in vertical section, of a second form or embodiment of the invention;

Fig. 8 is an'elevation, at an enlarged scale, of a portion of Fig. 7;

Fig. 9 is a sectional view, on line 9--9 of Fig. 8;

Fig. 10 is a sectional View on line 10-10 of Fig. 8;

Fig. 11 is a sectional view lonline 11-1'1 of Fig. s;

Fig. 12 is a sectional viewy on line 12-12 of Fig. 8; and y Fig. 13 is a perspectivev v iew ot-` one of the thread-cutting ChasersV shown in Figs. Z to 12, inclusive. Y

Referring to the form of the invention' which is illustrated in Figs. l to e, inclusive, of the drawings, and having reference at iirs't more particularly to Fig. l, there is shown a thread- .Cutting die comprising a body 21, provided with a blank-receiving opening 22, and a plurality or Chaser-receiving slots 23. In this example, there are four of these slots, each of which receives a thread-cutting Chaser 24.-, though the number willV depend somewhat upon the diameter of the stock or blank to be threaded. The number will vary from three to six or more in practice, but of course the design of the body or holder may have to be Varied to suit the number of chasers.

One important feature'of my invention which characterizes both forms is that the body and the chasers have sidewise interengaging means restraining the chasers against movement lengthwise of the axis ci the die, and providing for attachment oi each chaser to the body by movenient of the chaser, irst in one direction and then inv another direction to a position in which the 'Chaser is intercngaged with the body, and restrained against movement lengthwise of the axis. To this end, in the form shown in Figs. l to 6, inclusive, the slots arefradial, and have laterally widened portions, as by being provided with a plurality of pairs oi grooves one pair associated with each slot, the two grooves oi each. pair leading laterally in opposite directions, respectively, from the associated `slot,said grooves extending lengthwise of the axis o1 the die.

In this form, each Chaser is provided with two sets of oppositely and sidewise projecting tongues (best shown in Fig. 6), interengaged with the body, each set of tongues on each chaser com-' prising two pairs of tongues 2S and two pairs of tongues 27, four overlying one face of the body and four overlying the opposite face. The width of each tongue 26 in a generally radial direction is somewhat less than the widthof each groove 25, and the tongues 26 and 27 are separated by spaces 28, whose width is somewhat greater than the distance between the groove and the central opening 22. As a consequence, each chaser is detachable from the body by sliding radially along its slot toward the central opening to bring the two pairs of tongues 25 into registration. with the respective laterally widened portions of1 the slot, i. e., the grooves 25 on opposite sides or the slot, and-to bring the other two pairs of tonguesY 27 into registration with the central opening. This movement unlocks the Chaser, and permits the latter to slide in its slot lengthwise of the axis of the die. VDuring this sliding movement, the tongues 26 of one pair slide through the grooves 25, while the tongues 27 of one pair pass through the central opening Y22. Thus, any or all of the Chasers when worn or broken may be removed and replaced by 'new ones.

As the body will be made of a comparatively soft grade of steel, capable of flexing in the manner presently to be described, without danger of crystallizing and cracking, the body may be, and herein provided with sets of relatively hard inserts, such as cylindrical pins, comprising two pairs of pins 29 and two pairs of pins 30, to receive the wear of the chasers. Each tongue 26 overlies pin 29, and each tongue 27 overlies a pin 3G, as will be evident from a comparison of Figs. 2 and 5.

To retain the chasers in their proper positions in their respective slots, there is associated with each chaser a suitable retainer, herein a screw 3l extending loosely through a radial hole 32 in the body, and having screw-threaded engagement with a threaded hole 33 (best shown in Fig. 6) inthe chaser. the chasers may be dismcunted from the body in the manner hereinbefore described.

Another feature of the invention now to be described is r. sans for adjusting the body, consequently the chasers, to vary the diameter of the screw to be cut. To this end, in the forni of the invention illustrated in Figs. l to 5, inclu.u sive, the body is rendered expansible and contractible by providing the same with two slots 34 (see l'ig. 2), leading in opposite directions from the central opening 22, or it may be considered that there is a single slot interrupted by the central opening. To increase the flexibiliiy of the holder, each slot at its cuter end terminates in an opening 35, herein cylindrical. Thus,

lthe 'cody is quite thin on opposite sides of these openings, and is capable of bending with the requisite degree of freedom.

Adjustment of the holder by flexing the same is conveniently accomplished by the use of tapered adjusting screws 36 (best shown in Fig. 3), threaded into the body. These screws may be and herein are provided with hexagonal sockets 37,

to receive a tool by means of which they mayy be turned. .By turning the screws in the proper direction, the body may be expanded or allowed to contract at will, thereby furnishing an adjustment to vary the diameter of the screw to be out by the chasers.

To prevent the adjustment from being disturbed accidentally, I have provided two clamping screws 38, associated with the slots 34, rrespectively, and adapted to clamp the body about the adjusting screws 36 toprevent rotation cf the latter. As shown, each clamping screw provided at one end with a head 39, and extends,

first loosely through an opening 46at one side of the slot 34, then across the slot, then into a screw-threaded opening 4l, with which it has screw-threaded engagement. As a measure of safety, to prevent the clamping screw from being screwed so far as to cause danger of breakage of the body, and further, as a means to prevent loss of the clamping screws, each in the present example is provided with a safety stop 42, Vnormally `separated from the adjacent side of the body by a space 43. Each stop is conveniently secured to its screw by providing the latter with a reduced portion 44 to receive the stop, and the outer end of the screw is headed over or riveted, as at 45, to hold the stop in place.

Another feature of the invention which may be termed a blank guide will now be described, reference being had to Fig. 4. This guide is for therpurpose of guiding the blank or stock, and holding the same properly centered with relation to the chasers. As shown, the guide com- By first removing these screws,l

prises a plate 46, provided with an aperture 47 whose diameter is such that the blank or stock just slides freely through it, and is accurately centered. This plate is conveniently mounted for adjustment on the body by providing the latter with holes 48 lengthwise of the axis of rotation of the die to receive slidable pins 49, which may be clamped in any desired position within the range or adjustment by set screws 50, herein having knurled heads 5l'tov enable them to be turned with the fingers.

One of the pins 49 is permanently and rigidly aixed to the plate 46, as by providing the same with a reduced portion 52 passed through the plate, and riveted as at 53. Inasmuch as this particular die has an adjustable body, the remaining pin 49 is self-adjusting to compensate for adjustment of the body. This is conveniently accomplished in the present example by providing the remaining pin with a reduced portion 54, which extends through a radial, elongated slot 55 in the plate 46, the reduced portion extending thencethrough and secured as by riveting at 56 to a block 57, which is slidable radially in a groove 53 provided in the plate. Thus, the pin is capable of moving radially with relation to the plate when the body is being adjusted.

Referring to Fig. 5, it will be observed that the chaser is provided with, not only the usual chamfer represented by the line A-A, but also a bevel, represented by the line B-B (which may be either round or straight), herein round, the purpose of which is to bevel olf the endof the blank or stock, in case the latter is somewhat over size. This prevents the tearing and spoiling of threads, which sometimes occurs when the stock is somewhat larger than it should be.

In this form of the invention, the body is provided with handles 59, which are integral therewith and of cylindrical form. As shown, these handles are lightened by drilling holes 60 (see the left-hand portion of Fig. l) lengthwise of the handles. -When the handles are short, it is desirable to provide the outer end of each with arounded terminal portion in the form of a cap 61 to prevent injury to the palms of the hands. This cap is conveniently attached to the handle by providing the cap with a tapered portion 62, which'merges into the cylindrical surface of the handle, and is conveniently secured to the latter,

the chasers of the first form, is interengaged sidewise with the body. In this form, however, the chaser lis flush at its ends with the faces of the body (see Fig. l1). Interengagement of the chaser and the body in this case is had by providing the Chaser with two sets of tongues or teeth 67 and 68 (see Figs. 12 and 13), interengaged with correspondingly-shaped teeth on the body. The latter is provided/with lateral grooves 69, one associated with each slot 65, and extending lengthwise of the axis of the die, the width of each groove in a radial'direction being somewhat greaterV than the width of the tongues or teeth 67. The chaser is provided with a groove or space 70, between its two sets of tongues or teeth, and the width of this space is somewhat greater than the distance from thegroove 69 to the central opening 64. As a result, the chaser may be dismounted from the body by sliding the chaser radially inward to bring the tongues or teeth 67 into registration with the groove 69, and to bring the tongues or teeth 68 into registration with the central opening 64, thus unlocking the chaser from the body and permitting thechaser then to slide in the slot lengthwise of the axis of the die. To facilitate machining the tongues or teeth Vin the body, the latter as shown isprovided with grooves 71, adjacent the outer ends of the slots 65 (see Fig. 8). Here, as in the first form, the chasers are normally-secured in placev by radial screws 72.

In this form of the invention, as in the rst, the body is adjustable; but in this form, the means of adjustment, while having a general resemblance to the iirst form, differssomewhat in detail, more specically by the employment of a single adjusting screw and a single clamping screw. Referring to Fig. 8, the body is rendered ilexible by providing the same with two slots 73 and 74, the former being straight and the latter having an oblique portion 75, which extends to the side of the body. The slot 'Z3 terminates at its outer end in an opening 76 to increase the iiexibility. In this case, as already intimated, there is a single tapered adjusting screw 7'?. threaded into the body, and there is a single clamping screw '78. As these screws are like-the corresponding screws of the rst form, it is deemed unnecessary to describe them in detail.

This form, like the first, is provided with a blank guide (best shown in Fig. 10), which Ain all respects is like that of the'first form, and therefore needs no description.

In this form, the die is provided with tubular handles 79, having terminal caps 80 like those of the nrst form, but in this form, each handle is detachably secured to the body by providing the laf-Lier with a reduced threaded portion 8l, upon which is screwed a thirnble 82, the latter havinga reduced portion 83 inserted into the tubular handle, and suitably secured therein as bywelding at 84. Y

l-'aving thus described two embodiments of the invention, but without limiting myself thereto, what I claim and desire byy Letters Patent to secure is: *n

l. a iioread-cuttmg die, the combination of a body provided with a blank-receiving opening, a. plurality o chaser-receivingy slotsl leading from said opening, and a plurality of .sidewise grooves leading from said slots, respectively, transversely ci radial planes containing the axis of said openand a plurality of chasers received in and engaging both sides of said slots, respectively, said chas-ers being provided with sidewise projections interengaging sidewise with said body transversely oi said planes, each chaserbeing detachable from said body by movement in its slot radially inwardly to a position in which its projection regrs with the groove leading sidewise'from such slot and then enters and finally leaves such slot by movement lengthwise of the axis of said blankreceiving opening.

2. In a thread-cutting die, the combination oi" a body provided with a blank-receiving opening,k a plurality or" Chaser-receiving slots leading Vfrom said opening, and a plurality of chasers received in and engaging both sides of said slots, respectively, said body and said chasers being provided with sidewise interengaging, cooperative means providing for detachment of each chaser from said body by movement of such chaser'inwardly to-v ward the axis of the die and then longitudinally of said axis, said means including projections extending sidewise from said chasers, and transversely of said slots, considered with reference to radial planes containing said axis.

3.111 a thread-cutting die, the combination of a body provided with a blank-receiving opening, a plurality of chaser-receiving slots leading from said opening, and a plurality of chasers received in and engaging both sides of said slots, respectively, said body and said chasers being provided with sidewise interengaging, cooperative means normally preventing movement of such chaser lengthwiseof the axis of the die, and providing for detachment of such chaser from said body by movement of such Chaser first to a position in which it can move'lengthwise of said axis and then movement lengthwise of said axis, said means including projections extending sidewise from said chasers and transversely of said slots considered with reference to radial planes containing said axis.

4. In a thread-cutting die, the combination of a body provided with an axial, blank-receiving opening, a plurality of Chaser-receiving slots leading from said opening, and a plurality of pairs of sidewisegrooves, one pair associated with each slot, the two grooves of each pair leading laterally in opposite directions, respectively,-from the associated slot, and a plurality of thread-cutting chasers received in and engaging both sidesof said slots, respectively, each chaser being provided with a pair of oppositely projecting tongues interengaged sidewise with said body, each Chaser being detachable from said body by sliding along its slottoward said opening to bring its tongues into registration with the respective grooves leading from such slot, such Chaser being then slidable in its slot lengthwise of the axis of the die.

5. In a thread-cutting die, the combination ofa body provided with an axial, blank-receiving opening, a plurality of Chaser-receiving slots leading from said opening, and a plurality of pairs of sidewise grooves, one pair associated with each slot, the two grooves'of each pair leading sidewise in opposite directions, respectively `from the associated slot, anda plurality of thread-cutting chasers received in and ittingboth sides of said slots, respectively, each chaser vbeing provided with two pairs of sidewise, oppositelyfprojecting tongues interengagedl sidewise with said body, each Chaser being detachable from said body by sliding along its slot toward said openingto bring one pair of tongues .into registration with the respective grooves leadingfromsuch slot and tobring its other pair `of tongues into registration with said opening, such chaser being then slidable in its slot lengthwise of the axis of the die.

r6. In a thread-cutting die, the combination of two sets of sidewise oppositely projecting tongues interengaged sidewise with said body, each set comprising two pairs of sidewise tongues, each Chaser being-detachable-from said body by sliding along its slot toward said opening to bring one set of tongues into registration with the respec- Lillo tive grooves leading from such-slot and to bring the other set of tongues into registration with said opening, such Chaser being -then slidable .in its slot lengthwise of the axis of thedie.'

'7. In a thread-cutting die, the combinationr of a body provided with a blank-receiving opening, a plurality of Chaser-receiving slots and a plurality of sidewise grooves leading from said slots, respectively, considered with reference to radial planes containing the axis of said opening, and a plu.- rality of Chasers received in, and fitting both sides of said slots, respectively, each Chaser being provided with a sidewise projection interengagin'g sidewise with said body: between opposite end faces of said body, each Chaserbeing detachable from said body by movement inwardly toward said opening, which movement interrupts the-interengagement of its projection withsaid body and brings such projection into registration with i a plurality of chasers received'in and fitting both sides of said slots, respectively, each Chaser being provided with two-sidewisek projectionsinteren- Y gaging sidewise with said body between opposite end faces of the latter, each' chaser being detachable from said body by movement inwardly toward said opening, which movement interrupts the interengagement of its projections with said body and brings one projection into registration with the groove leading from the slot in which such Chaser is received, and then `movement of such Chaser lengthwise of said axis, which movement Carries one projection along such groove and the other along said opening lengthwise of the axis ofthe die.

9. In a thread-cutting die, the combination'of a body provided with a blank-receiving opening, and a plurality of Chaser-receiving slots leading outwardly from said opening, a plurality of chasers received in and engaging both sides of said slots, respectively, said body'and said chasers having sidewise intere'ngagingmeans interengaging sidewise with reference to radial planes containing thel axis of said opening and normally vrestraining said Chasers against movement lengthwise of the axis of the die, said means including projections extending sidewise from said chasers and transversely of said slots', and means normally to maintain such interengagenient. j

10. In athread-cutting die,the combination of a bcdyhaving opposite parallelrfac'es, a blankreceiving opening and a plurality 'of` chaserreceiving openings, a plurality of hard'inserts set into said body from both of said faces, and a plurality of chasers received insaid Chaser'- receiving openings, respectively, and having pro-r jections outwardly beyond said faces and/contacting with said inserts. f v f 11. In a thread-cutting die, the combination of a body provided with a central opening'anda plurality of radial openings leading from said central opening, and a plurality of thread-cutting chasers received and slidable radially in and en gaging both sides of saidradial openings, `respectively, and projecting into said central opening,` the radial dimension of each Chaser being greater than the root diameter Vof the thread to be cut by said chasers, each Chaser having means normally interlocked sidewise with said body and preventing movement of such Chaser lengthwise of the axis of 'rotation of the die, said means including projections extending sidewise from said chasers and transversely of said radial openings, each Chaser being movable radially inwardly a distance less than its radial dimension to bring a portion of such Chaser within the circle of said diameter and to unlock said Chaser from said body.

12. In athread-cutting die, the combination of a body provided' with a central opening and a plurality of other,v radial openings communicating with said central opening and having Closed, outer ends, a plurality of thread-cutting chasers movably mounted in said other openings, respectively, and projecting into said central opening, the radial dimension of each Chaser being greater than the root diameter of the thread to be cut by said chasers, the outer end of each Chaser engaging the'closed, outer end of the opening in which it is mounted, each Chaser having sidewise projecting means which extends transversely of the axis of rotation of the die and transversely of said other openings, and normally prevents movement of such Chaser longitudinally of said axis, each Chaser being movable radially inwardly a distance less than its radial dimension to bring a portion of such Chaser within the Circle of said diameter and to unlock said chaser' from said body.

l 1.In a thread-cutting die, the combination of a cody having opposite, generally parallel faces, said body being provided with a blank-receiving opening and a plurality of generally radial, chaserreceiving' slots extending from one of said faces to the other, and a plurality of thread-Cutting chasers received in and having portions engaging portions of both sides of said Chaser-receiving slots, respectively, said chasers having exposed faces corresponding to said faces of said body, said chasers and said body having interengaging means normally restraining said chasers against movement lengthwise of the axis of said blankreceiving opening, said means including projections, certain of which extend sidewise from said chasers and transversely of said sides of said slots, each Chaser being removable from its slot by sliding the saine freely inwardly toward said blankreceiving opening to bring its said sidewise extendingv projections fully into registration with said blank-receiving opening and its remaining projections into registration with a portion of its slot, and then moving said Chaser lengthwise oi' said axisout of said body. f

14. VIna'thread-Cutting die, the combination of abody having opposite, ygenerally parallel faces, said body being provided with a blank-receiving opening and a plurality of generally radial, chaserreceiving slots extending from one of said faces to the other, said body being also provided with a plurality of groovesextending from one of said faces to the'other lengthwise of the axis of said blank-receiving opening and leading sidewise from said slots,` and a plurality of thread-cutting Chasers received in and engaging both sides of said Chaser-receiving slots,k respectively, said chasers having exposed faces corresponding to said faces of said body, said chasers having means interengaging with said body and normally restraining said Chasers against movement lengthwise of saidaxis, said means including projections overlying said faces and normally out of registration with said grooves, each Chaser being removable from its slot by sliding the same freely 150 inwardly toward said blank-receiving opening to bring its said projections into registration with the groove leading from its slot, and then moving said chaser lengthwise or" said axis to cause one of its said projections to pass through such groove and out of said body.

l5. in a threadutting die, the combination oi' a body having opposite, generally parallel faces, said body being provided with a blank-receiving opening and a plurality of generally radial, Chaserreceiving slots extending from one of said faces to the other, a plurality of thread-cutting chasers received in and having portions engaging portions of both sides of said Chaser-receiving slots, respectively, said chasers having exposed faces corresponding to said faces of said body, said chasers and said body having interengaging means normally restraining said chasers against movement lengthwise of the axis of said blank-receiving opening, said means including projections, certain of which extend sidewise from said chasers and transversely of said sides of said slots, each Chaser being removable from its slot by sliding the same freely inwardly toward said blank-receiving opening to bring its said sidewise extending projections fully into registration with said blank-receiving opening and others into registration with a portion of its slot, and then moving said Chaser lengthwise of said axis out of said body, and means normally to secure said chasers against such inward sliding movement.

16. ln a thread-cutting die, the combination of a body having opposite, generally parallel faces, said body being provided with a blank-receiving opening and a plurality of generally radial, chaserreceiving slots extending from one of said faces to the other, and a plurality of thread-Cutting chasers received in and engaging both sides of said Chaser-receiving slots, respectively, said chasers having exposed faces corresponding to said faces of said body, said chasers and said body having interengaging means providing for detachment of each Chaser from said body by movement of such chaser rst radially inwardly toward said opening to a position in which such Chaser is in part at least within said opening and is unlocked from said body, and subsequently lengthwise of the axis of said opening, said means including projections extending sidewise from said chasers and transversely of radial planes Containing said axis.

17. In a thread-cuttng die, the combination ofV a body provided with a blank-receiving opening, a plurality of Chaser-receiving slots leading from said opening, and a plurality of chasers received in and engaging both sides of said slots, respectively, said chasers and said body being provided with interengaging means interengaging sidewise with said body transversely of planes containing the axis of said opening, each chaser being detachable from said body by movement radially from a position in which it is interengaged with said body, to a position in which such Chaser is not interengaged with said body, and then moving such chaser lengthwise of the axis of said opening.

18. In a thread-cutting die, the combination of a body having opposite, generally parallel faces, said body being provided with a blank-receiving opening and a plurality or" generally radial, Chaser-receiving slots extending from one of said faces to the other, and a plurality oi thread-Cutting chasers received in and having portions engaging portions of both sides oi said Chaser-receiving slots, respectively, said chasers having exposed faces corresponding to said faces of said body, said chasers and said body having interengaging means normally restraining said chasers against movement lengthwise of the axis of said blank-receiving opening, said means including projections extending sidewise from said Chasers and transversely of the sides of said slots, and including also other projections disposed radially outwardly with relation to the rst-mentioned projections, each Chaser being removable from its slot by sliding the same freely inwardly toward said blankfreceiving opening to bring its rstmentioned projection fully into said blank-receiving opening and to bring its second-mentioned projection into an enlarged portion of said slot, and then moving said Chaser lengthwise of said 11G axis out o said body.

19. In a thread-cutting die, the combination of a body provided with a blank-receiving opening, a plurality oi chaser-receiving slots leading from said opening about the latter, and a plu- 115 rality of chasers received in and having portions engaging portions of both sides of said slots, respectively, said chasers and said body being provided with interengaging means including a front projection and a rear projection on each Chaser, 120 said projections being of such dimensions and so arranged that when such chaser is moved radially inwardly until said front projection is wholly within said opening, such Chaser may be moved lengthwise of the axis of said opening, said front 125 projection passing axially therethrough, and said rear projection passing through an enlarged portion of its respective Chaser-receiving slot.

LUBEN k1\Tl'.KOLOl5"r". 13G 

